Which of the following elements has the highest second ionization energy?
A. Aluminum
B. Silicon
C. Magnesium
D. Sodium
Answer: Option D
Solution (By JKExamLibrary)
Sodium has the electronic configuration [Ne]3s1. After losing one electron to form Na+, it achieves a highly stable noble gas configuration ([Ne]). Removing a second electron from this stable core requires an exceptionally large amount of energy. Thus, sodium has the highest second ionization energy among these elements.
Explanation:
Mass number (A) = number of protons (Z) + number of neutrons (N). Electrons have negligible mass and are not counted. It is the total number of nucleons. Example: ¹²C has 6 protons + 6 neutrons = 12. Isotopes have same Z but different A due to varying N. Atomic mass (weight) is the weighted average.
Explanation:
Fertilizer grade is expressed as N-P₂O₅-K₂O percentage by mass. So 15-15-15 means 15% N, 15% P₂O₅ (not elemental P), and 15% K₂O (not elemental K). To convert P₂O₅ to P, multiply by 0.44; K₂O to K by 0.83. This is a balanced compound fertilizer providing all three primary macronutrients.
Explanation:
In a Daniel cell, the anode (where oxidation occurs) is a zinc rod immersed in ZnSO₄ solution. The cathode is a copper rod in CuSO₄ solution. Zinc is more reactive, so it loses electrons (Zn → Zn²⁺ + 2e⁻) and acts as the negative terminal of the cell.
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